View Full Version : A4 B5 1.8. Help ID this leak in my engine...

07-25-2013, 02:41 AM
Hey Guys

I have an A4 B5 1.8 non turbo FWD. I bought this car a couple of months ago and I am slowly restoring its condition fixing problems (Nothing major so far mechanically), and want to give the engine a really good going over now with timing belt and gaskets etc...

I have an oil leak in my car, evident by puddles accumulating each day under it, its a slow drip and I have only had to top off the oil once in a couple of months...

It seems to come from the rear of the engine and is more than likely coming from a number of different sources.

Just tonight I was looking at the rear of the engine with a torch and noticed a red substance which seems to be splattered at the rear of the engine block just before the firewall.. I took some pics.

Could someone chime in on what they think may be causing that? Its a fair but thicker than engine coolant which is red... but it looks like oil but its not the right colour to be oil as the puddles under my car are black.

I did a coolant flush not long ago and the coolant was a brown sludge which looked to me like green coolant had been topped up into it by the last owner, but on seeing this red crap in the back of the engine block perhaps its oil mixing with coolant somehow???

I am getting a timing belt installed and a bunch of gaskets and seals just to see if I can adress all the common leak areas at the very least as a precaution as the engine will be worked on anyway at the time of the timing belt being changes.

I do already have a oil cooler seal lined up ready to install... hoping the entire unit isnt screwed too..

What seals and gaskets commonly fail on the B5 A4's?

I have new and waiting to install:

Valve cover gasket
Oil Cooler Seal
Cam Chain tensioner gasket
Oil filter adaptor gasket
* All the gaskets and seals that come with ECS's Ultimate timing belt kit.

Have I missed anything?


07-25-2013, 05:58 PM
Bumpity bump?

07-25-2013, 06:02 PM
Probably coming from the can chain tensioner gasket and coolant neck
That come out the back of the head

07-25-2013, 10:21 PM
I hope thats the issue as I have a gasket for that on my desk... But would that leak a strange red coolant/oil?

Avant Nate
07-25-2013, 10:34 PM
Probably the coolant flange on the back of the block

07-26-2013, 01:23 AM
Yeh coolant flange, remove the intake hoses and get a mirror and have a look where the heater hoses join to the flange.

07-26-2013, 02:40 AM
ahh cool, Ill check it out.. might order one anyway and have it all done with the valve cover gasket... its not expensive and probably good to replace anyway.

Do you think its worth replacing the oil cooler while im there? I have a new seal already but do the units themselves fail much?

Keep in mind my car has done 240,000kms.

07-26-2013, 04:13 AM
If your replacing the coolant flange and gaskets, best too replace the oil cooler together so you don't go back and have to drain the coolant etc.
They tend to fail but i never had an issue with the oil cooler but higher km probs good idea to replace it all at once.

07-26-2013, 10:45 AM
Refer to this;


07-26-2013, 10:51 AM
Little word of advice...

DO NOT BUY ANY FORM OF AFTER MARKET coolant neck. Go straight down to the deal and buy the stock one from them. There is no after market solution that is good. In fact the after market one that I bought, came in a bag that made it seem like it was a stock part. It was not. It did come from a vendor who makes parts for Audi as stock parts, but the quality was WAY bellow the item that I bought from the dealer. The plastic from the part sourced at the dealership was 2 times thicker in some sections.